Abstract: Process of acid attack with sulphuric acid of a phosphate source comprising calcium or not comprising calcium for a predetermined time period ranging from 20 to 180 minutes in the conditions wherein the molar ratio of sulphate from the sulphuric acid and possibly from the phosphate source to the calcium present in the phosphate source ranges from 0.6 to 0.8, and the content in P2O5 in the attack tank is of less than 6%.

Abstract: Process of acid attack with sulphuric acid of a phosphate source comprising calcium or not comprising calcium for a predetermined time period ranging from 20 to 180 minutes in the conditions wherein the molar ratio of sulphate from the sulphuric acid and possibly from the phosphate source to the calcium present in the phosphate source ranges from 0.6 to 0.8, and the content in P2O5 in the attack tank is of less than 6%.

Abstract: Process for the production of sodium chloride crystals from a sodium chloride brine contaminated by potassium chloride and sulphate ions, according to which a calcium compound (32) is added to the brine (48) to crystallize glauberite (35), which is isolated, the resulting aqueous solution (36) is subjected to evaporation to crystallize sodium chloride (40), which is collected, and the aqueous mother liquor (41) from the crystallization of the sodium chloride is subjected to cooling (42) to crystallize glaserite (45).

Abstract: A process for crystallization of an inorganic substance includes preparing a supersaturated solution of the inorganic substance to be crystallized in a solvent which is a liquid; forcing a stream of the supersaturated solution upwardly through successively a fluidized bed distributor of a fluidized bed reactor and a bed of crystals arranged above the fluidized bed distributor with a pressure effective to cause fluidization of the bed of crystals, the fluidized bed distributor dividing the stream of supersaturated solution into thin, substantially parallel and vertical jets; maintaining the fluidized bed distributor at a temperature which is uniform and at which the inorganic substance to be crystallized from the supersaturated solution is lower than or equal to the concentration corresponding to saturation; and controlling the temperature of the fluidized bed distributor to cause the stream of supersaturated solution in the fluidized bed distributor to undergo a temperature change which is insufficient to des

Abstract: Process for producing sodium carbonate, according to which a sodium sesquicarbonate ore is successively calcined and dispersed in an aqueous solution substantially saturated with hydrated sodium carbonate and the resulting aqueous suspension is subjected to an aging, at the end of which an aqueous mixture of a powder comprising hydrated sodium carbonate crystals is collected. During the aging, a fine particle size fraction is extracted from the aqueous suspension and removed.

Abstract: Process for producing sodium carbonate, according to which a sodium sesquicarbonate ore is successively calcined and dispersed in an aqueous solution substantially saturated with hydrated sodium carbonate and the resulting aqueous suspension is subjected to an aging, at the end of which an aqueous mixture of a powder comprising hydrated sodium carbonate crystals is collected. During the aging, a fine particle size fraction is extracted from the aqueous suspension and removed.

Abstract: Process for enriching crude salt, in which the crude salt is ground and then cooled in a saturated aqueous sodium chloride solution, to a temperature below the anhydrous sodium chloride to sodium chloride dihydrate transition temperature, a stock of a powder comprising sodium chloride crystals is collected from the cooling step and the powder is subjected to particle-size fractionation from which a fine particle-size fraction and a coarse particle-size fraction comprising the enriched salt are collected.

Abstract: Process for the coproduction of calcium carbonate and sodium hydroxide, comprisingcausticizing sodium carbonate with milk of lime;separating the calcium carbonate and the sodium hydroxide formed in the causticizing stage; andcarbonating a mixture of milk of lime and of the calcium carbonate resulting from the causticizing stage.

Abstract: Process for the manufacture of an industrial aqueous solution of sodium chloride, according to which an aqueous mixture (12) containing an aqueous solution of sodium chloride and of polyvalent metals is prepared by introducing into water (10) a solid product (8) collected from the dry-route treatment, with sodium bicarbonate (4), of smokes (2) containing hydrogen chloride, and the said aqueous medium (12) is treated in order to remove the polyvalent metals therefrom.

Abstract: Method for producing an industrial aqueous sodium chloride solution (22) in which an aqueous solution of sodium chloride (20) containing polyvalent metals and constituting a mother liquor obtained from the precipitation (14) of hydroxides of said metals from an aqueous solution (6) of hydrochloric acid is obtained from washing (3,4) fumes (1) containing hydrogen chloride and originating from the oxidation of chlorinated products, is treated on a chelating Na-type resin. The aqueous sodium chloride solution obtained in this manner has applications in the production of aqueous sodium hydroxide solutions by means of electrolysis or electrodialysis and in the production of sodium chloride crystals by means of evaporation.

Abstract: Installation for the crystallization of an inorganic substance in a crystal slurry, by desupersaturation of a supersaturated solution, the installation comprising a crystallization chamber which has a vertical axis and is divided into a central zone (4) and an annular zone (5), a device (9, 10) designed to bring about a vertical translation of the slurry in the central zone (4) and a translation in the opposite direction in the annular zone (5), a device (8) for withdrawing slurry, comprising a tube (23, 24) which opens into one of the abovementioned zones, a member (14) for mechanical shearing of the slurry, comprising, a disc (17) carrying a ring of shearing teeth (19), and a tube (6, 31) passing through the cover (30) and serving to introduce anhydrous sodium carbonate, the tube (31) having a prolongation inside the crystallization chamber, over which prolongation a film of water is caused to circulate.

Abstract: Process for purifying a gas containing nitric oxide, in which a gas containing oxygen and sulphur dioxide is used and the gas is treated with sodium carbonate hydrate at a temperature of between 320 and 500K.

Abstract: Process for the manufacture of sodium bicarbonate particles having an ovoid or spherical shape, the process preparing an aqueous solution of sodium bicarbonate, which is supersaturated; circulating the aqueous solution supersaturated in sodium bicarbonate through a bed of crystals in order to cause the bed to be a mobile bed in which the crystals are in continuous motion, and to cause crystallization of the sodium bicarbonate particles and at least partial desupersaturation of the aqueous solution supersaturated in sodium bicarbonate to provide a mother liquor and, withdrawing the sodium bicarbonate particles from the bed.

Abstract: Process for the production of salt in which sodium chloride is crystallized in the form of spheres by evaporation of a sodium chloride brine and the spheres obtained are then broken up. The salt produced by the process is particularly suitable for the food industry.

Abstract: Process for removing an industrial residue containing sodium sulphate, in which the sodium sulphate in the residue 7 is treated with a calcium salt 12 to precipitate calcium sulphate 13, which is sent to a rock salt deposit 15, from which an aqueous solution of sodium chloride 16 is withdrawn.The process applies to the residues from the desulphurization of fumes by means of sodium bicarbonate.

Abstract: Process for the production of salt in which sodium chloride is crystallized in the form of spheres by evaporation of a sodium chloride brine and the spheres obtained are then broken up. The salt produced by the process is particularly suitable for the food industry.

Abstract: Process for the production of a water-insoluble nitrogeneous organic base, from an aqueous solution of alkali metal bicarbonate and the base hydrochloride, according to which the solution (11) is treated with a complement of the base hydrochloride (12), and the resultant liquid (18) is treated with a basic agent (30) capable of decomposing the hydrochloride. The invention is applied to the regeneration of the amine in the process for the manufacture of sodium bicarbonate by the amines method.

Abstract: An organic solution (2) of a water-immiscible chloride of an organic cation is mixed with a basic reagent and with water (3) in a reaction chamber (1), the mixture (6) which has reacted is transferred into a phase separation chamber (5) where the organic solution of the base (8) and an aqueous phase (7) containing a solid residue are separated and at least a part of a sludge (9) formed between the organic solution and the aqueous phase which have separated is recycled into the reaction chamber (1).

Abstract: In order to reduce the tendency to decompose of particles or granules of alkali metal chlorites and to enhance their stability, said particles or granules are completely coated with an inorganic salt or a mixture of such salts which are compatible with the chlorite and with each other, e.g. nitrates, carbonates, bicarbonates, phosphates, silicates and chlorides, especially alkali metal salts and alkaline earth metal salts thereof. The coating may be carried out by any conventional coating process, e.g. by contacting the particles with a solution of the stabilizing salts under vaporizing conditions in a rotating inclined disk, a rotary drum, or in a fluidized bed.